Currently, sleeve spanners are used with matched sleeves for locking or releasing screwing elements of various sizes. Thereby, use of the sleeve spanners are convenient in many applications.
However, the size of the spanner is fixed for one corresponding sleeve. Thereby, for a predetermined sleeve, if no corresponding spanner, the sleeve cannot be used. Thereby, in this situation, the peripheral elements around the narrow workplace must be detached. Thereby, the labor of the workers is increased and the working time is prolonged results in increased cost.
Referring to FIG. 1, a prior art disclosed in U.S. Pat. No. 6,098,502, in the prior art, a variety of sleeves are disclosed. In FIGS. 1 and 2, the periphery of the sleeve has a round shape and in FIGS. 3 to 6, the periphery of the sleeve has a hexagonal shape. In FIGS. 7 and 8, the sleeve has threes layers, the upper two layers have hexagonal shapes and the lower layer has a round shape. Thereby, the advantage of this prior art is that the sleeve can be matched with opened spanners, flower type spanners or sleeve spanners. Thereby, it is convenient. If the sleeve is used with opened spanner or flower type spanner, the total size is reduced so that it can be used in narrow spaces.
However, above mentioned prior art still has above described deficiency, i.e., the sleeves must be used with matched spanners. It is often that the workers take time to find the spanners. Furthermore, the sleeves shown in FIGS. 7 and 8 of the prior art have a larger volume so that it still have above mentioned problem.